Highly demarcated structural alterations in the brain and impaired social incentive learning in Tbx1 heterozygous mice.

Copy number variants (CNVs) are robustly associated with psychiatric disorders and changes in brain structures. However, because CNVs contain many genes, the precise gene-phenotype relationship remains unclear. Although various volumetric alterations in the brains of 22q11.2 CNV carriers have been identified in humans and mouse models, it is unknown how each gene encoded in the 22q11.2 region contributes to structural alterations, associated mental illnesses, and their dimensions. Our previous studies identified Tbx1, a T-box family transcription factor encoded in the 22q11.2 CNV, as a driver gene for social interaction and communication, spatial and working memory, and cognitive flexibility. However, it remains unclear how TBX1 impacts the volumes of various brain regions and their functionally linked behavioral dimensions. In this study, we used volumetric magnetic resonance imaging analysis to comprehensively evaluate brain region volumes and behavioral alterations relevant to affected structures in congenic Tbx1 heterozygous mice. Our data showed that the volumes of the anterior and posterior portions of the amygdaloid complex and its surrounding cortical regions were most robustly reduced in Tbx1 heterozygous mice. In an amygdala-dependent task, Tbx1 heterozygous mice were impaired in their ability to learn the incentive value of a social partner. The volumes of the primary and secondary auditory cortexes were increased, and acoustic, but not non-acoustic, sensorimotor gating was impaired in Tbx1 heterozygous mice. Our findings identify the brain's regional volume alterations and their relevant behavioral dimensions associated with Tbx1 heterozygosity.

Preventive effect of one-session brief focused attention meditation on state fatigue: Resting state functional magnetic resonance imaging study.

INTRODUCTION: The extended practice of meditation may reduce the influence of state fatigue by changing neurocognitive processing. However, little is known about the preventive effects of one-session brief focused attention meditation (FAM) on state fatigue in healthy participants or its potential neural mechanisms. This study examined the preventive effects of one-session brief FAM on state fatigue and its neural correlates using resting-state functional MRI (rsfMRI) measurements. METHODS: We randomly divided 56 meditation-naïve participants into FAM and control groups. After the first rsfMRI scan, each group performed a 10-minute each condition while wearing a functional near-infrared spectroscopy (fNIRS) device for assessing brain activity. Subsequently, following a second rsfMRI scan, the participants completed a fatigue-inducing task (a Go/NoGo task) for 60 min. We evaluated the temporal changes in the Go/NoGo task performance of participants as an indicator of state fatigue. We then calculated changes in the resting-state functional connectivity (rsFC) of the rsfMRI from before to after each condition and compared them between groups. We also evaluated neural correlates between the changes in rsFC and state fatigue. RESULTS AND DISCUSSION: The fNIRS measurements indicated differences in brain activity during each condition between the FAM and control groups, showing decreased medial prefrontal cortex activity and decreased functional connectivity between the medial prefrontal cortex and middle frontal gyrus. The control group exhibited a decrement in Go/NoGo task performance over time, whereas the FAM group did not. These results, thus, suggested that FAM could prevent state fatigue. Compared with the control group, the rsFC analysis revealed a significant increase in the connectivity between the left dorsomedial prefrontal cortex and right superior parietal lobule in the FAM group, suggesting a modification of attention regulation by cognitive effort. In the control group, increased connectivity was observed between the bilateral posterior cingulate cortex and left inferior occipital gyrus, which might be associated with poor attention regulation and reduced higher-order cognitive function. Additionally, the change in the rsFC of the control group was related to state fatigue. CONCLUSION: Our findings suggested that one session of 10-minute FAM could prevent behavioral state fatigue by employing cognitive effort to modify attention regulation as well as suppressing poor attention regulation and reduced higher-order cognitive function.

Right amygdala and caudate activation patterns predict implicit attitudes toward people with autism spectrum disorders and physical disabilities, respectively.

Attitudes toward people with disabilities tend to be negative, regardless of the visibility of the disorder traits. Individuals with autism spectrum disorder (ASD) experience stigmatization that is rooted in negative attitudes or prejudice toward them because of their social awkwardness. The neural underpinnings of attitudes toward people with disabilities remain unclear. In this study, we focused on implicit attitudes toward people with ASD and physical disabilities, which are more visible than ASD, and investigated whether implicit attitudes were predicted by using neural activity with multivoxel pattern analysis (MVPA) in the prejudice network. Thirty-six, right-handed, Japanese, university students without disabilities participated. Two implicit association tests (IAT) toward people with ASD and physical disabilities revealed negative implicit attitudes. In the MRI scanner, participants performed a one-back task by using the same picture sets of IATs to examine their neural responses toward people with ASD and physical disabilities. According to the MVPA results, activation patterns of the right amygdala and right caudate significantly predicted implicit attitudes toward people with ASD and physical disabilities, respectively. These results suggest that implicit attitudes toward ASD and physical disabilities can be predicted by using neural signals from different regions within the prejudice network.

Tbx1, a gene encoded in 22q11.2 copy number variant, is a link between alterations in fimbria myelination and cognitive speed in mice.

Copy number variants (CNVs) have provided a reliable entry point to identify the structural correlates of atypical cognitive development. Hemizygous deletion of human chromosome 22q11.2 is associated with impaired cognitive function; however, the mechanisms by which the CNVs contribute to cognitive deficits via diverse structural alterations in the brain remain unclear. This study aimed to determine the cellular basis of the link between alterations in brain structure and cognitive functions in mice with a heterozygous deletion of Tbx1, one of the 22q11.2-encoded genes. Ex vivo whole-brain diffusion-tensor imaging (DTI)-magnetic resonance imaging (MRI) in Tbx1 heterozygous mice indicated that the fimbria was the only region with significant myelin alteration. Electron microscopic and histological analyses showed that Tbx1 heterozygous mice exhibited an apparent absence of large myelinated axons and thicker myelin in medium axons in the fimbria, resulting in an overall decrease in myelin. The fimbria of Tbx1 heterozygous mice showed reduced mRNA levels of Ng2, a gene required to produce oligodendrocyte precursor cells. Moreover, postnatal progenitor cells derived from the subventricular zone, a source of oligodendrocytes in the fimbria, produced fewer oligodendrocytes in vitro. Behavioral analyses of these mice showed selectively slower acquisition of spatial memory and cognitive flexibility with no effects on their accuracy or sensory or motor capacities. Our findings provide a genetic and cellular basis for the compromised cognitive speed in patients with 22q11.2 hemizygous deletion.

Effects of pain associated with orthodontic tooth movement on tactile sensation of periodontal ligaments.

OBJECTIVES: Pain associated with orthodontic tooth movement reportedly reduces periodontal ligament tactile sensation. However, the mechanism associated with the central nervous system remains unclear. This study was conducted by measuring somatosensory evoked magnetic fields (SEFs) during mechanical stimulation of teeth as they were being moved by separator elastics. Findings clarified the effects of pain on periodontal ligament tactile sensation during orthodontic tooth movement. MATERIALS AND METHODS: Using magnetoencephalography, SEFs were measured during the application of mechanical stimuli to the mandibular right first molars of 23 right-handed healthy participants (0 h). Separator elastics were subsequently inserted into the mesial and distal interdental portions of the mandibular right first molars. The same mechanical stimuli were applied again 24 h later while the SEFs were measured (24 h). After each SEF measurements, pain was also evaluated using the Visual Analog Scale (VAS). RESULTS: The VAS values were significantly higher at 24 h than at 0 h (p < 0.05). No significant difference in the peak latencies was found between those obtained at 0 h and 24 h, but the intensities around 40.0 ms in the contralateral hemisphere were significantly lower at 24 h than at 0 h (p < 0.01). CONCLUSIONS: Pain associated with orthodontic tooth movement might suppress periodontal ligament tactile sensation in the primary somatosensory cortex. CLINICAL RELEVANCE: Pain associated with orthodontic tooth movement might affect periodontal ligament sensation, consequently causing discomfort during occlusion.

Common and distinct neural bases of multiple positive emotion regulation strategies: A functional magnetic resonance imaging study.

Appropriate emotion regulation is crucially involved in mental and physical health. The neural basis of negative but not positive emotion regulation has been well investigated. Several strategies should be compared to elucidate the neural correlates of positive emotion regulation. However, there are no studies on multiple positive emotion regulation strategies. We aimed to investigate the neural correlates of positive emotion regulation with multiple emotion regulation strategies and identify common and differential brain areas involved in positive emotion upregulation. We acquired functional magnetic resonance imaging data from healthy college student volunteers while they upregulated positive emotions through instructed strategies or by viewing positive pictures. The instructed strategies included Attentional Deployment, Cognitive Change, and Response Modulation. These strategies increased subjective positive emotions and activation of the prefrontal cortex (PFC) and anterior cingulate cortex (ACC). Region of interest analysis revealed greater activation of the ventral striatum during positive emotion regulation. There are different networks involved in Cognitive Change and Response Modulation. Our findings indicate that multiple strategies for positive emotion upregulation involve common (e.g., PFC, ACC, and ventral striatum) and unique networks.

Sex-Dependent Effects of the APOE ɛ4 Allele on Behavioral Traits and White Matter Structures in Young Adults.

The APOE ɛ4 allele is associated with a risk of Alzheimer's disease in the elderly, with the association being pronounced in females. Conversely, findings of the effects of the APOE ɛ4 allele in young adults are mixed. Here, we investigated the sex-genotype interaction effects of the APOE ɛ4 allele on cognitive functions as well as brain structures among 1258 young adults. After adjusting for multiple comparisons, there were significant effects of the interaction between sex and the number of APOE ɛ4 allele on some speed tasks (e.g., simple processing speed tasks and the reverse Stroop task) as well as on regional white matter volume (rWMV). The observed sex-genotype interaction conferred better cognitive performance and greater rWMV in the anterior frontal and precentral white matter areas in females having more APOE ɛ4 alleles and reduced rWMV in the same areas in male having more APOE ɛ4 alleles. These findings support the long-debated antagonistic pleiotropic effects of the APOE ɛ4 allele in females.

Application of Diffusion Tensor Imaging Fiber Tractography for Human Masseter Muscle.

Diffusion tensor imaging (DTI) has been used to indicate the direction of nerve and muscle fibers by using the characteristics that water molecules preferentially diffuse along the fibrous structure. However, DTI fiber tractography for multipennate muscles, such as the masseter muscle, is challenging due to a lack of data regarding the imaging parameters. This study aimed to determine the optimal DTI parameters for masseter muscle fiber tractography. A 27-year-old healthy man voluntarily underwent DTI and T1-weighted magnetic resonance imaging of the right masseter muscle. Four imaging parameter settings were created by combining the following parameters that particularly affect the signal-to-noise ratio: b-value, number of excitations (NEX), and number of motion probing gradient (MPG) directions. DTI fiber tractography was performed using specific software for each parameter setting. The length and orientation of the muscle fibers in each layer were calculated. As a result, the masseter muscle fibers of each layer were identified on DTI. Although the detected fiber length was affected significantly by the imaging parameters, the fiber orientation was insignificantly affected. The appropriate combination of the b-value, NEX, and the number of MPG directions for masseter muscle fiber tractography could be determined based on previously reported anatomical data of the masseter muscle fibers. DTI may enable the non-invasive evaluation of masseter muscle fiber length and orientation. Elucidation of the details of masseter muscle fiber orientation is useful in evaluating stomatognathic biomechanics and muscle disorders.

Morphological comparison of masseter muscle fibres in the mandibular rest and open positions using diffusion tensor imaging.

BACKGROUND: The masseter muscle has a complicated multipennate internal structure and exhibits functional differentiation when performing various stomatognathic functions. It is important to understand the internal structural changes of the muscle during functioning to elucidate characteristic muscle disorders such as local myalgia. Diffusion tensor imaging (DTI) may be useful for investigating the internal structural features of muscle. OBJECTIVES: To evaluate the features of masseter muscle fibres in human participants using DTI fibre tractography, and to elucidate the structural differences in the masseter muscle between the mandibular rest and open positions. METHODS: Five healthy men (age 31 ± 7 years) underwent DTI and T1-weighted MRI of the right masseter muscle in the mandibular rest and open positions. MR images were used as a reference for muscle layer segmentation (superficial, intermediate, and deep). DTI fibre tractography of the masseter muscle was performed and the orientation of the DTI fibres was analysed in each layer using coordinates based on the Frankfurt horizontal plane. RESULTS: The DTI fibre orientation of the deep layer significantly changed between the mandibular rest and open positions in the frontal plane (p < 0.05, Wilcoxon rank sum test). However, no significant change was found in the superficial and intermediate layers. CONCLUSION: DTI fibre tractography confirmed regional differences in the orientation change of the masseter muscle fibres between different mandibular positions. The results may support the existence of functional partitioning inside the masseter muscle and suggest that DTI may be useful for the evaluation of muscle fibres in multipennate muscles.

Polygenic risk score for bipolar disorder associates with divergent thinking and brain structures in the prefrontal cortex.

It has been hypothesized that a higher genetic risk of bipolar disorder (BD) is associated with greater creativity. Given the clinical importance of bipolar disorder and the importance of creativity to human society and cultural development, it is essential to reveal their associations and the neural basis of the genetic risk of bipolar disorder to gain insight into its etiology. However, despite the previous demonstration of the associations of polygenic risk score (PRS) of BD and creative jobs, the associations of BD-PRS and creativity measured by the divergent thinking (CMDT) and regional gray matter volume (rGMV) as well as regional white matter volume (rWMV) have not been investigated. Using psychological analyses and whole-brain voxel-by-voxel analyses, we examined these potential associations in 1558 young, typically developing adult students. After adjusting for confounding variables and multiple comparisons, a greater BD-PRS was associated with a greater total CMDT fluency score, and a significant relationship was found in fluency subscores. A greater BD-PRS was also associated with lower total mood disturbance. Neuroimaging analyses revealed that the BD-PRS was associated with greater rGMV in the right inferior frontal gyrus, which is a consistently affected area in BD, as well as a greater rWMV in the left middle frontal gyrus, which has been suggested to play a central role in the increased creativity associated with the risk of BD with creativity. These findings suggest a relationship between the genetic risk of BD and CMDT and prefrontal cortical structures among young educated individuals.

Virtual training leads to physical, cognitive and neural benefits in healthy adults.

Physical activity, such as high-intensity intermittent aerobic exercise (HIE), can improve executive functions. Although performing strength or aerobic training might be problematic or not feasible for someone. An experimental situation where there is no actual movement, but the body shows physiological reactions, is during the illusion through immersive virtual reality (IVR). We aimed to demonstrate whether a virtual HIE-based intervention (vHIE) performed exclusively by the own virtual body has physical, cognitive, and neural benefits on the real body. 45 healthy young adults (cross-over design) experienced HIE training in IVR (i.e., the virtual body performed eight sets of 30 s of running followed by 30 s of slow walking, while the subject is completely still) in two random-ordered conditions (administered in two sessions one week apart): the virtual body is displayed in first-person perspective (1PP) or third-person perspective (3PP). During the vHIE, we recorded the heart rate and subjective questionnaires to confirm the effectiveness of the illusion; before and after vHIE, we measured cortical hemodynamic changes in the participants' left dorsolateral prefrontal cortex (lDLPFC) using the fNIRS device during the Stroop task to test our main hypothesis. Preliminary, we confirmed that the illusion was effective: during the vHIE in 1PP, subjects' heart rate increased coherently with the virtual movements, and they reported subjective feelings of ownership and agency. Primarily, subjects were faster in executing the Stroop task after the vHIE in 1PP; also, the lDLPFC activity increased coherently. Clinically, these results might be exploited to train cognition and body simultaneously. Theoretically, we proved that the sense of body ownership and agency can affect other parameters, even in the absence of actual movements.

Originality of divergent thinking is associated with working memory-related brain activity: Evidence from a large sample study.

The originality of creativity measured by divergent thinking (CMDT) is a unique variable that is positively correlated with psychometric intelligence and other psychological measures. Here, we aimed to determine the associations of CMDT originality/fluency scores and brain activity associated with working memory (WM) and simple cognitive processes during the N-back paradigm in a cohort of 1221 young adults. We observed that originality/fluency scores were associated with greater brain activity during the 0-back simple cognitive task and 2-back WM task in key nodes of the ventral attention system in the right hemisphere. Further, subjects with higher originality/fluency scores showed lower task-induced deactivations in areas of the default mode network, especially during the 2-back task. Psychological analyses revealed the associations of originality/fluency scores with both psychometric intelligence and systemizing. We also observed the effects of interaction between sex and originality/fluency scores on functional activity during the 0-back task in posterior parts of the default mode network together with other areas as well as simple processing speed. These results indicate that the originality of CMDT is associated with (a) greater activation of the ventral attention system, which is involved in reorienting attention and (b) reduced task-induced deactivation of the default mode network, which is indicative of alterations in attentional reallocation, and (c) cognitive correlates of originality of CMDT and revealed sex differences in these associations.

Convergent creative thinking performance is associated with white matter structures: Evidence from a large sample study.

In laboratory settings, creativity is measured using tasks of divergent as well as convergent thinking. It has been suggested that brain connectivity is important for creativity. In the present study, we investigated the associations of convergent thinking performance of compound Remote Associates Test (CRAT) with fractional anisotropy (FA) in diffusion tensor imaging and regional white matter (WM) volume (rWMV) in voxel-based morphometry in a large sample of healthy young adults (360 males and 280 females; mean age: 20.9 years, SD â€‹= â€‹1.6). We showed that CRAT performance was positively correlated with WM pathway property (i.e., FA) in the left fronto-occipital fasciculus and the left inferior longitudinal fasciculus, which play important roles in processing of language and concept. Further, CRAT performance was negatively correlated with rWMV in the widespread frontal temporal subcortical and cerebellar WM areas, suggesting the unique association of convergent thinking with WM connectivity.

Increased grey matter volume of the right superior temporal gyrus in healthy children with autistic cognitive style: A VBM study.

The empathizing-systemizing model describes human cognitive style using empathizing (the drive to identify another's mental state and respond appropriately) and systemizing (the drive to assess or construct rule-based systems). 'Brain type' was envisioned to explain individual differences in cognitive style based on the discrepancy of the two drives. In this model, individuals with autism spectrum disorder (ASD), a neurodevelopmental disorder, have extremely stronger systemizing. Revealing the underlying mechanisms of individual differences in cognitive style might contribute to elucidation of the pathology of ASD. We used voxel-based morphometry to compare the brain structures among the brain types (those who have stronger empathizing, those who have equally stronger drive to both, and those who have stronger systemizing) in 207 healthy children (age range: 5-15). Results showed that children with stronger systemizing had significantly greater grey matter volume of the right superior temporal gyrus (rSTG) than the others. The brain region, a distinctive brain structure of those with stronger systemizing, was overlapped with that of children with ASD. The rSTG is involved in detailed perceptual processing in social cognition, which is partially related to stronger systemizing. Our results contribute to elucidation of the underlying mechanisms of individual differences in cognitive style.

A Common CACNA1C Gene Risk Variant has Sex-Dependent Effects on Behavioral Traits and Brain Functional Activity.

Genome-wide association studies have suggested that allelic variations in the CACNA1C gene confer susceptibility to schizophrenia and bipolar disorder only in women. Here we investigated the sex-specific effects of the CACNA1C variant rs1024582 on psychiatry-related traits, brain activity during tasks and rest, and brain volume in 1207 normal male and female subjects. After correcting for multiple comparisons, there were significant interaction effects between sex and the minor allele of this polymorphism on the hostile behavior subscale scores of the Coronary-Prone Type Scale mediated by higher scores in female carriers of the minor allele. Imaging analyses revealed significant interaction effects between sex and the minor allele on fractional amplitude of low-frequency fluctuations in the right dorsolateral prefrontal cortex and on brain activity during the 2-back task in areas of the right posterior cingulate cortex, right thalamus, and right hippocampus, which were all mediated by reduced activity in female carriers of the minor allele. Our results demonstrated that the rs1024582 risk variant of CACNA1C is associated with reduced activity in the frontolimbic regions at rest and during a working memory task as well as with greater hostility in females in the healthy population.

A single nucleotide polymorphism (-250 A/C) of the GFAP gene is associated with brain structures and cerebral blood flow.

AIM: Glial fibrillary acidic protein (GFAP), the intermediate filament protein expressed in astrocytes, plays a key role in many aspects of brain function through communication with neurons or blood vessels. A common single nucleotide polymorphism (SNP), GFAP -250 C/A (rs2070935), is associated with the transcriptional regulation of GFAP, which can potentially result in the genotype-specific brain structure. This study aimed to verify the biological effects of the GFAP variants on brain structure and function. METHODS: We investigated the associations between the GFAP variants and magnetic resonance imaging findings, including gray and white matter volumes, white matter integrity, and resting arterial blood flow, from 1212 healthy Japanese subjects. RESULTS: The GFAP -250 C/A genotype was significantly associated with total gray matter volume, total white matter volume, average mean diffusivity, and mean cerebral blood flow. In voxel-by-voxel analyses, the GFAP genotype showed significant associations with the regional gray and white matter volumes in the inferior frontal lobe and corpus callosum, the regional mean diffusivity in the left posterior region, and the regional cerebral blood flow throughout the brain. CONCLUSION: This study revealed a common SNP that is significantly associated with multiple global brain structure parameters.

The pitfall of empathic concern with chronic fatigue after a disaster in young adults.

BACKGROUND: Empathic concern (EC) is an important interpersonal resilience factor that represents positive adaptation, such as "relating to others" (a factor of posttraumatic growth [PTG]) after disaster. However, controversy exists regarding whether the changes in EC (e.g., the intra-personal change between the acute phase and the disillusionment phase) positively or negatively affect mental health after a disaster. We hypothesized that increased EC may increase chronic fatigue due to over-adjustment (hypothesis 1). We also hypothesized that increasing the changes in "relating to others" could decrease the changes in chronic fatigue (hypothesis 2). METHODS: Forty-nine young, healthy volunteers (M/F: 36/13; age at 3 months after the disaster [3 months]: mean ± SD: 21.1 ± 1.7 years) underwent assessments of EC using the Japanese version of the Interpersonal Reactivity Index, chronic fatigue using the Japanese version of the Checklist Individual Strength (CIS-J) questionnaire, and "relating to others" using the Japanese version of the PTG inventory during the acute phase (3 months) and the disillusionment phase (1 year after the disaster). Pearson product moment correlations at 3 months and 1 year were determined for all scores related to EC. The changes (delta = degree of change from 3 months to 1 year) or scores at 1 year were entered into linear structural equation systems to test the hypotheses. RESULTS: The delta of EC positively affected the delta of the CIS-J, and the delta of relating to others negatively affected the delta of the CIS-J. Both the EC and relating to others scores were negatively associated with the CIS-J score at 1 year. These results were in accordance with hypothesis 1 and 2. CONCLUSIONS: We demonstrated the opposite effects of 2 types of ECs, i.e., stability (inherent disposition) and flexibility (degree of change), on the degree of chronic fatigue. Increasing EC with increasing chronic fatigue, but not the change in relating to others, may be a red flag for individuals during the disillusionment phase.

Anxiety increases visual attention to hedonic foods: A preliminary eye-tracking study on the impact of the interplay between integral and incidental affect on foods.

Two types of affect influence consumers' attention: incidental affect unrelated to a particular perception or judgment and integral affect directly related to the particular options under consideration. Although integral and incidental affect likely coexist on a regular basis, the claim that both concurrently guide consumers' attention has thus far received little attention. To fill this gap, the present study investigated the effects of the interplay of integral and incidental affect on the visual processing of food. Food labels play an essential role in attracting consumer attention. Food labels include sources of integral affect (e.g., food type, pictures), and consumers often view food labels under the influence of incidental affect (e.g., an unrelated anxiety-inducing message or personal experience). According to the appraisal tendency framework, incidental experiences of anxiety can enhance affective processing of food due to the uncertainty associated with anxiety. In our study, participants were first subjected to manipulation of an incidental emotion (anxiety, anger, or neutral). Then, they passively viewed food labels, including pictures and nutrient labels, for hedonic and healthy foods. Subject's eye movements were tracked during this stage of the study. Our results showed that the induction of incidental anxiety, but not anger or neutral feelings, led to greater visual attention on hedonic foods only. These findings shed light on the interplay between incidental and integral affect in consumer information processing, demonstrating that the co-occurrence of incidental anxiety and integral hedonic feelings enhance visual attention to food.

Approach or avoidance: Neural correlates of intelligence evaluation from faces.

Intelligence is among the key determinants of power and social status in modern societies. In this functional magnetic resonance imaging study, we examined the neural correlates of intelligence evaluation from faces. Participants underwent scans while they evaluated the perceived intelligence and friendliness of faces. We found that medial orbitofrontal cortex activity increased linearly with friendliness ratings. The relationship between perceived intelligence and brain activity was positively linear in the right caudate nucleus and U-shaped (i.e., strong responses to unintelligent-looking or intelligent-looking faces) in the right anterior insula/inferior frontal gyrus. Perceived intelligence was also significantly positively correlated with both friendliness and attractiveness. Furthermore, intelligence rating scores had a positive linear effect on reaction times in the friendliness rating task, suggesting that participants had greater conflicts when making friendliness judgments for faces that appeared to belong to intelligent individuals. In addition, the degree of this effect predicted individual differences in the positive linear modulatory effect of intelligence scores in the right caudate nucleus. Our interpretation was that the activity in the caudate nucleus revealed an approach-avoidance conflict with regard to highly intelligent people, that is, they were perceived as attractive but also potentially threatening. Although our interpretations are merely suggestive because we did not measure the approach-avoidance behaviors directly, our findings have important implications for understanding the dynamics of human interaction in modern societies that increasingly allocate power and status based on intelligence.

Impact of frequency of internet use on development of brain structures and verbal intelligence: Longitudinal analyses.

Excessive internet use is shown to be cross sectionally associated with lower cognitive functioning and reduced volume of several brain areas. However, the effects of daily internet use on the development of verbal intelligence and brain structures have not been investigated. Here, we cross sectionally examined the effects of the frequency of internet use on regional gray/white matter volume (rGMV/rWMV) and verbal intelligence as well as their longitudinal changes after 3.0 ± 0.3 (standard deviation) years in a large sample of children recruited from the general population (mean age, 11.2 ± 3.1 years; range, 5.7-18.4 years). Although there were no significant associations in cross sectional analyses, a higher frequency of internet use was found to be associated with decrease of verbal intelligence and smaller increase in rGMV and rWMV of widespread brain areas after a few years in longitudinal analyses. These areas involve areas related to language processing, attention and executive functions, emotion, and reward. In conclusion, frequent internet use is directly or indirectly associated with decrease of verbal intelligence and development to smaller gray matter volume at later stages.